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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Syntheses of Highly Strained Energetic Molecules and Development of New Synthetic Methodology

Wu, An-hsiang 05 1900 (has links)
The objective of this study was to synthesize new energetic, strained, saturated polycyclic compounds. For this purpose, new methodology has been developed, as follows: (i) Ketenes have been generated in situ via treatment of aldo-, keto- or alkenoic acid with either toluenesulfonyl chloride or 2-chloro-1-methylpyridfniurn iodide (Mulkaiyama's reagent). The reactive intermediates thereby generated have been found to undergo intramolecular [2+2] cycloaddition reactions in these systems.
2

Transition metal-catalyzed C-N bond formation via addition of nitrogennucleophiles towards alkenes and related tandem cyclization reactions

Xing, Dong, 邢栋 January 2011 (has links)
published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy
3

The synthesis of some substituted 7-(1-Naphthyl)- Benz(a)Anthracenes

Lewis, Claude Irenius 29 November 2012 (has links)
Many benz(a)anthracene derivatives are able to produce cancer in the experimental animal. There is a correlation between the calculated total electronic charge of the K-region and this carcinogenic activity. There is also ample proof that benz(a)anthracene derivatives are honed to the skin through quinoid type bonds in the K"region. However, the prediction of physiological activity of benz(a)anthracenes is still unreliable because of the limitations of the theoretical model described by existing theories. The purpose of this work was to synthesize some substituted benz(a)anthracenes with a shielded K-region and with a different L-region electron density than in 7-phenyl-bena(a)anthracene in the hope of increasing our knowledge regarding molecular structure-physiological relationship. / Ph. D.
4

Syntheses and the Structures of Polymethylpolycyclic and Polycyclic "Cage" Molecules

Zhao, Dalian 05 1900 (has links)
The structures of Diels-Alder cycloaddition of cyclopentadiene to 2,6-dimethyl-p-benzoquinone and methylcyclopentadiene to 2,6-dimethyl-p-benzoquinone were assigned by analysis of 1-D and 2-D proton and carbon-13 NMR spectra. The structures of the cycloadduct of methylcyclopentadiene to 2,6-dimethyl-p-benzoquinone and that of the corresponding intramolecular [2+2] photocyclization product were also obtained by single crystal X-ray structural analysis. As the second part of the study, a new polycyclic "cage" molecule, a substituted trishomocubane isomer, was synthesized. In this synthesis, reductive bond cleavage followed by Dieckmann condensation was employed. Wolff-Kishner reduction then was used to convert a β-keto ester "cage" molecule to the corresponding carboxylic acid. A compound that possesses twofold symmetry was isolated from reaction product mixture. The structure of this compound has been established by single crystal X-ray crystallography.
5

Synthesis of Polycyclic "Cage" Molecules

Ren, Chien-Tai 08 1900 (has links)
The synthesis of a novel, cage spiro-oxetane was carried out. Pentacyclo[5.4.0.0^2,6.0^3,10.0^5,9]undecane-8- one (PCUD-8-one) undergoes one-carbon homologation to a mixture of endo- and exo- PCUD-carboxaldehydes which then are converted into 8,8-bis(hydroxymethyl)PCUD. The monotosylate obtained via reaction of 8,8- bis(hydroxymethyl)PCUD with tosyl chloride(1 equivalent) reacts with sodium hydride to afford the corresponding spiro-oxetane via intramolecular Williamson reaction. Six new substituted heptacyclo[6.6.0.0^2,6.0^3,13.0^4,11. 0^5,9.0^10,14]tetradecanes (HCTD) were synthesized. These compounds will be used as substrates in a photoelectron spectroscopic study. The ring-expansion reaction of PCUD-8-one with ethyl diazoacetate in the presence of BF_3:OEt_2 was performed. The major product was converted into an alcohol, and the structure of the 3,5-dinitrobenzoate of this alcohol was elucidated by single crystal x-ray structural analysis.

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